Process for stabilizing and refining tung oil and product thereof



nited States arent flice Y v2,867,639 Patented J''n. 6, 19,59

PROCESS FOR STABILIZING` AND TUNG OIL AND PRODUCT THEREOF John Andrew Watts, Long Beach, Miss., assig'nor to The Tungoliny Company, Inc., Long Beach, Miss., a corporation of Mississippi No Drawingg: ApplicatinAuglist 1'3, 1954' Serial No. 449,799 s cretini. (ci. 26o-42s) l `his inventionv relates to a nevv and improved'process for stabilizing and refining tung oil and the highly refined product thereof, the properties of which make it particularly useful-for therapeutic and cosmetic purposes.

Raw tung oil is unstable because of the tendency of glyceryl ct-elaeostearate, which ordinarily comprises about 75-85% of the oil, t'o change over tothe solid -form in the presence of light. The instability greatly limits its usefulness. The tendency toward tti-compound formati'o'n may be checked by heating or thermoli'zing4 the oil to a' temperature of about 475-'500 F. butI this' treatment is disadvantageous in as much asthe heat treated oil'becornes so highly viscous that it is difficult to pour and also darkens considerably in color. Heating, furthermore, does not eliminate theheavy odor which many people find objectionable. These objectionable characteristics,name1y high viscosity, odor and high'degre'of coloration, which frequently causes staining, limitecnsiderably therapeutic and cosmetic use of the oil. n I

The object of this invention is to provide a process f'orproducing a stable tung oil of light color and substantially reduced, inoffensive odor, which is further characterized by low viscosity.

Another object is to produce a stable, refined tungoil which isv particularly useful'for therapeutic andc'os'ine'tic use.

Other objects and advantages vvill become obvious from the following detailed description. n n

The process comprisesv heating ravv tungV oil under agitation to a temperature of about 17o-190 F., pieterabiy about=180 E., adding about 5 @10% ofjaf'iieiy dit/itiesv solid adsbrbeiitti the` bi1 with continued g1-gitatibii; maintaining the mixture-bf' oir and adsorbentl at the 1701190 tetiperatute fbjr` about' 15 to' 30 ini tites, pefera'biyf about' 20 minutes, under continued agitation aridthe'n" Separating the' adsorbent from the oil i `any suitable manner as, for example, by'filtration o'r centifuging.:

Af'portidiifr ther tratedoii is'tbeti heatdwith coittii'e'd agitation'to about 475-500 preferably about 500 F. The-higher the temperature, the shorter, desiably, is the time of tieatment. For example; the' oil is preferably main'tainedat a' temperature of about 475 F. for about to 15 minutes.' When the o`il is heated'to 500 F.,- heating may be discontinued a's soonjas the oil reaches temperature. Preferably, the' oil is raised to the high*therrnolizing temperature gradually; The thermblize'd'bn is thenr'ecom'bined with the tung oiiwhich lhas been giventhe treatment With solidadsbrbent' only,

namely the' portion which has 'been lsubjected to la' maximuni temperatureo'f about 190'? it des'iid, the" sblidK-adso'rbetitmay be added to tbe raw oit-prior to heatingtb the 17o-'190 temperature. Theioil'may also be partially heated as, for examplefto G-'160 F. prior to addition' of the adsorbent and then htatettvtbI 170:190? E. e

The" tung oil mayfbetreated in two separate' batches, vif desired, one batch being treated with solid adsorbent 2 as aforedescribed and then heated to 475-500 F. and another batch being given only the treatmentwith solid adsorbent and being subjected to a maxirnum temperature of about 190 F. The two treated batches may then be combined in the requisite proportions of thermolized to non-thermolized' oil.

Treatment of the tung oil vvith a solid adsorbent removes both color and odorous impurities; The temperaturev of the oill during such treatment should not be less than about 170 F., since substantial decolorization and deodorization are not obtained belovv this ternperature. Temperatures above about 190 F. should be avoided since above this temperature viscosityV of the oil increases rapidly. e Although theportiony of the tung oil which is heat treated at 475f500 F.` becomes highly viscous, this is of no moinent since the viscosity is sharply reduced upon recombination with the low-viscosity tung oil which has not been subjected to high temperatures.

Not only does the high temperature treatment stabilize the portion of the oil s treated against `conversion into the solid -forrn, but I have found that addition y0f a portion of such oil to non-therrnoli'zed oil alsostabilizes the'yresulting mixture. To obtain such stabilization at least 20% lof the tung oil must be' given' the high tenipe'rature treatment.v So long as it is' inH minor proportion, the amount of high-temperature treated'oil'may be increased as much asV desired if viscosity of thewfinished product is not an important factor for the particular use. However, if a low-viscosity product is desired, it is preferable not toK increase the' proportion of the therinolized oil by much overl 30%. VViscosity of` thefirial product is not appreciably higherthanth'at of the Alov!- viscosity', V non-'therrnclized portion when thel proportion of thermolizedoil is about 20 to 30%'. Viscosit'yincreasesmar'kedly With proportions above 30%;l In general use of about 25% of the ther'rnolized o'il isiparticularly satisfaetor'y. y v,

Anyv suitable solid adsorbent caribe usedv as the decoloizing and deodrizing medium such as vactivated clay, activated charcoal, fullers earth, bentonite, silica andthe like. A minimurnof about 5%I on the weight of the tung oil is usually necessary to'hobtain the desired de c'olorizatiori and deodorization. The amunt may be inereasedw asv much as desiredalthough",A iii' general, quantities in excess of about 10%' do not produce any marked increase in eicacy. I Y i* The'l finished product is a light straw color ascornpared with the rather dark yellow of a' stabilized,` th'e'rmolized oil. Odor is considerably reduced' as compared b'ot'h'with ravv tung` oil` a rid ordinary high-temperature stabilized'oil and isiveryrnild and inoffensive. Viscosityof the adsorbent-treated tungy oil containingrab'out 20 tov30% `of a l high-temperature treated portion is about Q to'S;v usually R, on the Gardner scaleas compared with visco'sfies of Z4v to' Z6 of the usual heat-stabilized o'iI. n e

The"'stabilized tung oil product, because of its low viscosity, freedom from impurities, light colorl vvhich eliminates staining, and lack of offensive o'dor', is particularly suitable for therapeutic and'cosmetic use; H

Tung'oil is a highly ec'acious healing agent; apparently because" it stimulates rapid growthand regeneration of new tissue;v It is very effective for use topically in the treatment of ederr'riatosis,` burns, ulcerations', sprains, sorene's'sflcerations,surgical 'Wounds andthe like. The healing" action 'isle'nhanc'ed bythe highly penetrative properties" oftlieoil'.l Although the oil, of itself, is apparently not an antiseptic, it prevents the development'of' secondary infectionsprobably because' of its stimulatory yeffect on' the production of new tissue.

The tung oil is non-toxic and is markedly" free from allergic reaction. For example, over individuals, including 12 dermatological patients, a large group of high school students, a group of oli-ice workers and 18 tung mill workers received an application of tung oil on the forearm and were checked 24 hours later by a physician specializing in diseases of the skin. All tests were negative for primary irritation and sensitivity reaction.

TheV following chart summarizes clinical applications of tung oil and findings which demonstrate its therapeutic efficacy. The tung oil used was stabilized with a 25% portion which had been heated to 500 F. y

(l) Simple lacerations; 56 cases; wound left open and oil applied every other day; average healing time- 3 to 7 days; average disability time using tung oil-overall average of 0.48 day lost; average disability time, tung oil not used-same.

(2) Simple lacerations sutured; 157 cases; wound left open and oil applied every other day; average healing time-6 to 10 days; average disability time using tung oil-overall average of 0.48 day work lost; average disability time, tung oil not used-2 to 3 days lost.

p (3) Severe trauma with lacerations; 43 cases; wound left open, Ylight splint applied, oil applied every day for four days then every other day; average healing time- 3 weeks; average disability time using tung oil-average 9 days work lost; average disability time tung oil not used-16 days lost.

(4) Severe trauma with small fractures and macerated tissue; 72 cases; wound left open, Tobruk-type cast or splint with window applied; oil applied every day for 5 days, then every other day; average healing time-4 to 6 weeks; overall average disability time using'tung oil-21 days work lost; average disability time tung oil not used- 34 days lost.

(5) Small fractures; 43 cases; light splint applied, massaged with oil every other day for one week, splint removed in one Week, oil then massaged into fracture area every 3 days; average healing time-3 to 4 weeks; average disability time using tung oil-11 days work lost; average disability time tung oil not used-17 days lost.

(6) Severe sprains and contusions; 129 cases; oil massaged into wrenched joint and swollen tissues for minutes, massage repeated daily; average healing time-7 to 12 days; average disability time using tung oil-5% days Work lost; average disability time, tung oil not used--12 days lost.

(7) Sacroiliac strains; 30 cases; Regens position, sedation, reduced, and then oil massaged into back at sacroiliac area for 1 to 5 days; average healing time-1 to 5 days; average disability time using tung oil-3.3 days work lost; average disability time, tung oil not used- 12 days lost.

(8) VVaricose ulcers Vwith recent industrial injury; 14 cases; treated the recent injury which in these 14 cases were contusions and also the ulcer area daily for 3 to 8 days; average healing time-in 3 to 8 days contusion was healed and ulcer improved; average disability time using tung oil-l3 healed in average of 5 days with improvements in ulcer; average disability time, tung oil not used- 3 weeks lost. Y Y

(9) Old sinuses and ulcerations on skin of feet and llegs associated with old massive compound fractures; 6 cases; novacainized and curettement of sinuses, oil then poured into curetted sinuses daily for 5 days, after that twice a week; average healing time 1 to 3 months; average disability time using tung oil-6 weeks work lost; average disability time, tung oil not used-4 months.

(l0) Abscesses with cellulitis and lymphangitis; 43 cases; abcesses incised, oil poured into abscessed area, cellulitis given gentle massage with oil daily; average healing time-14 to 16 days; average disability time using tung oil-8 days work lost; average disability time, tung `oil not used-15 days.

(11) First degree burns; 9 cases; oil applied one day, patient told to use it several days; average disability time using tung oil-none; average disability time, tung oil not used-none.

(l2) Second degree burns; 11 cases; oil applied daily for 3 to 6 days, patient told to continue using it; average healing time-3 to 6 days; yaverage disability time using tung oil-41/2 days work lost; average disability time, tung oil not used- 9 days.

(13) Third degree burns; 11 cases; mild debridement, oil applied to burned area moderate pressure dressing (it was necessary to graft skin in 5 of these cases), burns dressed every 2 to 3 days and oil applied, 5 grafts dressed every 3 days and oil applied; average healing time-2% to 8 weeks; average disability time using tung oil-61/2 weeks work lost; average disability time, tung o-il not used-3 months.

(14) Punctured wounds; 53 cases; oil rubbed in one time and applied to depth of Wound; average healing time-1 day; average disability time using tung oil-none; average disability time, tung oil not used-3 to 4 days.

(15) Elective cases, chielly removal of old scars, moles, cysts and biopsies of breasts, all closedby suture; 8l cases; oil poured into fresh wound, then suture taken, sutures removed on 6 to 10th day, non infection, all healing primary; average disability time using tung oil-none; average disability time, tung o-il not used- 5 days.

In the foregoing clinical test series, 763 cases were treated with tung oil, healing was Vcomplete and disability time was reduced an average of 50% as compared with similar cases treated by other methods.

Although this invention has been described with reference to illustrative embodiments thereof, it will be apparent to those skilled in the art that it may be embodied in otherforms but within thev scope of the appended claims.

I claim:

1. A process for stabilizing and refining tung oil which comprises treating tung oil at a temperature of about -190 F. with at least about 5% of a solid adsorbent for at least about 15 minutes to effect decolorization and deodorization without substantially increasing the viscosity of said oil; removing the solid adsorbent, heating a minor proportion comprising at least about 20% of the tung oil after said treatment With solid adsorbent to a temperature of about 475-500 F., said temperature being maintained for up to about 15 minutes, and combining said high-temperature treated portion with the major proportion of the adsorbentltreated oil thejmaximum temperature to which said major proportion of tung Voil is subjected being about 190 F.

Y170--190 F. with at least about 5% of a finely-divided solid adsorbent for at least about 15 minutes to eect decolorization and deodorization without substantially increasing the viscosity of said oil; removing the solid adsorbent, then heating to a temperature of about 475- 500 F., said temperature being maintained for up to about 15 minutes, and then admixing a minor proportion comprising at least 20% of said high-temperature treated oil with a major proportion of tung oil which has been treated with a finely-divided solid adsorbent at a temperature of about 170-190 F., said temperature being the maximum temperature to Which said major proportion of tung oil is subjected.

3. The process of claim 2 in which the solid adsorbent comprises at least about 5% to 10% of the tung oil.

4. The process of claim 3 in which treatment of the tung oil with the solid adsorbent is continued for about 15 to 30 minutes.

5. The process of claim 4 in which the proportion of high-temperature treated oil to oil treated at a maximum temperature of 17o-190 F. is about 20 to 30%.

6. A process for stabilizing and refining tung oil which comprises treating tung oil at a temperature of about 180 F. for about 20 minutes with about 5 to 10% of a solid adsorbent comprising activated clay, removing the solid adsorbent, heating about 20 to 30% of said oil to a temperature of about 500 F. aud then admixing said References Cited in the le of this patent high-fmpel'atlll'e treated Oil With the tung Oil Which UNITED STATES PATENTS 111;?) obtzen subjected to a maximum temperature of about 2,380,394 Berger et al. July 31, 1945 7. The process of claim 5 in which the solid adsorbent 5 2418921 Berger et al Apr' 15 1947 is activated charcoal. OTHER REFERENCES 8. A stable, rened tung oil having a viscosity of about information on China Wood Oil, by G. H Stevens Q to S on theGardner scale, and characterized by sub- (1924), p 5 stantially less odor than the untreated oil and light color, Bailey; Industrial Oil and Fat Products, published said oil being substantially stable against formation of 1 by Interscience (New York), 1951 (pp. 426-428 and 664 glyceryl-,B-elaeostearate. relied on). 

1. A PROCESS FOR STABILIZING AND REFINING TUNG OIL WHICH COMPRISES TREATING TUNG OIL AT A TEMPERATURE OF ABOUT 170-190*F. WITH AT LEAST ABOUT 5% OF A SOLID ADSORBENT FOR AT LEAST ABOUT 15 MINUTES TO EFFECT DECOLORIZATION AND DEODORIZATION WITHOUT SUBSTANTIALLY INCREASING THE VISCOSITY OF SAID OIL; REMOVING THE SOLID ADSORBENT, HEATING A MINOR PROPORTION COMPRISING AT LEAST ABOUT 20% OF THE TUNG OIL AFTER SAID TREATMENT WITH SOLID ADSORDENT TO A TEMPERATURE OF ABOUT 475-500*F., SAID TEMPERATURE BEING MAINTAINED FOR UP TO ABOUT 15 MINUTES, AND COMBINING SAID HIGH-TEMPERATURE TREATED PORTION WITH THE MAJOR PROPORTION OF THE ADSORBENT-TREATED OIL THE MAXIMUM TEMPERATURE TO WHICH SAID MAJOR PROPORTION OF TUNG OIL IS SUBJECTED BEING ABOUT 190*F.
 8. A STABLE, REFINED TUNG OIL HAVING A VISCOSITY OF ABOUT Q TO S ON THE GARDNER SCALE, AND CHARACTERIZED BY SUBSTANTIALLY LESS ODOR THAN THE UNTREATED OIL AND LIGHT COLOR, SAID OIL BEING SUBSTANTIALLY STABLE AGAINST FORMATION OF GLYCERYL-B-ELAEOSTEARATE. 